Hydraulic underreamer



ug 8, 1933- J. J. SANTIAGO 1,921,135

HYDRAULIC UNDERREAMER Filed March 7, 1930.

Patented Aug. 8, 1933 lliTE) STATES HYDRAULIC UNDER/KEMER .lames J. Santiago, Los Angeles, Calif., assigner to Grant, Los Angeles, Calif.

ppiieation March 7, 1930. Serial No. 434,155

7 Claims.

This invention has to do with expansive reaming tools, commonly known as underreamers, of the type actuated by hydraulic pressure.

A general object of the invention is to provide a simple compact and rugged form of expansive reamer or underreamer, actuated to collapsed position by one means, typically a spring, and is actuated to expanded position by hydraulic pressure, and preferably the hydraulic pressure or the circulation fluid which is pumped down through rotary drill pipes to and through a rotary rearner.

In the preferred and illustrative form which I am about to describe in detail, a tubular cutter carrying body is provided, and within the body and between the several cutters I arrange a vertically movable plunger which can be inoved upwardly by spring pressure and downwardly by hydraulic pressure. The relative downward movement of the plunger causes outward expansive movement of the cutters; while relative upward movement of the plunger causes or allows contractive movement of the cutters. And a valvular arrangement is provided whereby the full pressure of the circulation nuid is utilized i'or loweringr the plunger and expanding the cutters; the circulation pressure is relieved, and uid iow permitted onward through and to the various parts of the underreamer, only when the plunger has reached its lowermost point of travel with the cutters locked in expanded position.

For the purpose of a specific and detailed description oi` an illustrative forni and embodiment oi the invention, but not for the purpose of limiting the invention to details hereinafter explained I refer to the accompanying drawing in which:

Figure l is a longitudinal central section of the typical forni of my underreamer, showing the cutters contracted;

Fig. 2 is a similar section showing the cutter expanded; and

Figs. 3, 4 and 5 are cross sections on line 3-3,

4-4 and 5-5, respectively, ci Figure 2.

In the drawing, a suitable tubular body is shown at I0, fashioned at its upper end for the .usual tool joint connection at 1l with the lower presents an upwardly facing surface against shoulder 32 under which the upper (Cl. Z55-74) which the pressure of the circulating iluid acts to torce the plunger down.

The cutters, generally designated by the letter C, are mounted in slots which extend through the body wall; `and are movable in and out through those slots. The plunger P, below the piston l5, and the cutters, are so formed and interrelated that downward movement of the plunger wedges the cutters apart and. upward movement of the plunger allows the cutters to inove inwardly. Seeing that the plunger moves up and down, the cutters are coniined longitudinally by tting fairly closely lengthwise in the body slots.v

Although the relative wedging action between the plunger and cutters can, of course, be obtained with a plunger of uniform taper, it is desirable to so form the plunger and cutters that expansive actionv of the cuters is obtained by a relatively short movement and also that, when the plunger reaches its final position, the cutters are locked in their outward expanded positions, and do not depend upon any wedge or diagonal face to hold them lin expand position. For those reasons, and also because it may be desirable to have cutters which are expanded wholly or mostly at their upper I here show a typical in'terdorniation of plunger and cutters,

which I will now describe.

The cutters, as here illustrated, are made up of what I term a cutter carrier and a cutter roller 26 mounted to rotate on an axis pin 2'? which is mounted in the carrier. The carrier 25 is the part of the cutter which cooperates directly with the plunger. This carrier nts the body slots fairly tightly in a longitudinal direction, and also fits them snugly in width, The rear edges or" the cutter carriers have laterally pro-Y jecting wings 23 which overhang the inner edges oi the body slots and bear outwav ly against the body wall when the cutters are expanded. This is seen plainly by reference to Figs. 4 and 5. The plunger, immediately under piston 15, has a comparatively klarge cylindric or substantially cylindric part 30, whose diameter, however, is somewhat smaller than the diameter of body bore 14, so as to leave an annular space between the plunger part 3o and the body wall for entry of cutter wings 28 when the tool is expanded. See Figure fi. The upper part of the cutter carrier has a haelt surface 31 which bears back against this large part of the plunger when expanded.

Immediately beneath the plunger part 30 there is a rather abrupt diagonal downwardly facing end of the shown in Figure 2. It is, however, not necessary that the plunger fully reach this lower limiting position. Valve 54 is not raised off its seat until the plunger has moved so far downwardly as iully to expand the cutters-the large plunger part 30 has passed downwardly avconsiderable distance below the upper ends of the cutters before valve'e is raised. And therein lies another advantage in having a relatively abrupt eXpansion oi the cutters take place on the first downward movement of the plunger, and in thereafter having the plunger part 30 move straight down between the expanded cutters without expanding them further. With this arrangement it makes no great difference just where the plunger thereafter stops-that the relieved fluid pressure is not suicient to force the plunger much below the point at which valve 54 is raised;

When the parts have reached such an expanded position as shown in Figure 2, then the circulation fluid passes by valve 54 and down through the plunger bore. At points which are then below the lower ends of the cutters, a portion of the circulating liquid passes out through plunger openings 60 into bore 14. Thence this liquid passes outwardly and upwardly through circulation ports 6l which direct the circulation upwardly and outwardly immediately beneath the cutters. It will be noted that this circulation, in reaching the ports 6l, passes through the lower part of body bore i4' below the cutters, and thus keeps that part of the bore washed free of any accumulated settlement which might otherwise iill the bore and prevent the upward movement of collar 4e when it is desired to contract the reamer.

Another portion of the circulating liquid is passed through the spring bore 40 below collar 44. 'Ihe plunger extension 45 has small spaced openings 52 through its wall, and through these openings at least a part of the liquid circulation is delivered into the spring bore and washes that bore free from accumulated settlement. Otherwise accumulation and settlement of solid matter from the circulating liquid mud is very apt to iill up the spring chamber to such an extent that the spring cannot operate.

And finally part of the liquid circulation may pass into the spring bore directly from the lower end of the plunger; but it is preferred that the lower plunger end, when in the expanded position of Figure 2, be either close to or rest upon the joint pin 42; so that liquid circulation will be forced to take place through the various distributive openings leading through the wall of the plunger. It is for this purpose, among others, that itis desirable although not necessary that the relief of pressure by raising of valve 54 be at such a rate that the plunger will be forced downwardly close or quite to its lowermost position as shown in Figure 2. The liquid circulation which passes into and through the spring bore, passes out of that bore through the circulation passages of drill bit below.

I claim:

l. In an hydraulically actuated underreamer, the combination oi a tubular body with cutterreceiving slots through its tubular wall, cutters movable inwardly and outwardly in said slots, a plunger' having a part fitting the body interior to receive fluid pressure from above, the plunger and cutters being so formed that downward movement of the plunger under duid pressure causes outward expansive movement ci the cutters, means tending to move tl e plunger upwardly, said plunger having a collar located below the lower ends of the cutters and which is moved upwardly along with the plunger and into clamping contact with the lower ends of the cutters.

2. In an hydraulically actuated underreamer, the combination of a tubular body with cutterreceiving slots through its tubular wall, cutters movable inwardly and outwardly in slots, a plunger having a part tting body interior to e fluid pressure from above, plunger and s being so formed that downward movement nger under fluid pressure causes outnsive movement or" the cutters, means to plunger upwardly, the

move the having a longitudinal circulation bore therethrough, a downwardly seating valve a"apted to clos-e the bore against downward pasoi iiuid, a relatively movable valve rod within the plunger bore and extending out of the plunger bottom, and a part supported by the body with whichthe lower end ofthe valve rod contacts when the plunger is lowered under :duid pressure.

3. In an hydraulically actuated underreamer, the combination of a tubular body with cutterreceiving slots through its tubular wall, cutters movable inwardly and outwardly in said slots, a plunger having a part fitting the body interior to receive iluid pressure from above, the plunger and cutters being so formed that downward moveinent of the plunger under iiuid pressure causes outward expansive movement of the cutters, means tending to move the plunger upwardly, said plunger having a collar located below the lower ends of the cutters and which is moved upwardly along with the plunger and into clamping contact with the lower ends or the cutters, the plunger having a longitudinal circulation bore therethrough, a downwardly seating valve adapted to close the bore against downward passage of fluid, a relatively movable valve rod within the plunger bore and extending out oi the plunger bottom, and a part supported by the body with which the lower end of the valve rod contactsy when the plunger is lowered under iluid pressure.

4l. In an hydraulic underreamer, the combination of a tubular body having longitudinally extending slots through its wall, cutters mounted in the said wall slots and movable in and out therethrough, a plunger having a part which fits the body interior to take liquid pressure from above and thereby to cause downward movement of the plunger, a longitudinal liquid passage bore through the plunger, a downwardly seating valve normally closing the plunger bore against downward passage ofv liquid, the plunger having an upper comparatively large and substantially cylindric part and having, below said cylindric part, an abrupt diagonal cutter expanding surface, and having below said expanding surfacel a relatively smaller part against which the cutters bear inwardly when the plunger is in its upper normal position, means for normally holding the plunger in its upper position, and means acting to lift said valve after the plunger has moved down to a position wherein its relatively large and substantially cylindric part is between the cutters.

5. In an hydraulic underreamer, the combination of a tubular body having longitudinally eX- tending slots through its wall, cutters mounted in the said wall slots and movable in and out therethrough, a plunger having a part which lts the body interior to take liquid pressure from above and thereby to cause downward movement of the plunger, a longitudinal liquid passage bore through the plunger, a downwardly seating valve normally closing the plunger bore against downward passage of liquid, the plunger having an upper comparatively large and substantially cylindric part and having, below said cylindric part, an abrupt diagonal cutter expanding surface, and having below said expanding surface a relatively smaller part against which the cutters bear inwardly when the plunger is in its upper normal position, a spring pressing the plunger upwardly, a collar connected with the plunger at a point below the cutters and moved upwardly by the spring into clamping engagement with the lower ends of the cutters, and` means acting to lift said valve 01T its seat after the plunger has moved downwardly to a point where its said larger and substantially cylindrio part has entered between the cutters.

6. In an expansive reamer, the combination of a cutter holding body, cutters therein movable in and out for contraction and expansion, a cutter' expanding member movable with relation to the cutters to expand them on relative movement in one direction and allow them to contract on relative movement in the opposite direction, means moving4 the member in said last mentioned direction, and means actuated by said 'moving means to engage and clamp the cutters in contracted position.

7. In'an expansive reamer, the combination of a cutter holding body, cutters therein movable in and out for contraction and expansion, a cutter expanding plunger movable longitudinally with relation to the cutters to expand them on movement in one direction and allow them to contract on movement in the opposite direction, a spring tending to move the plunger in said cutter contracting direction, and means actuated by said moving means to engage and clamp the cutters in contracted position.

JAMES J. SANTIAGO. 

